We recently migrated our joomla/ K2 website to a new server. Since the move, whenever we create a new K2 item, or edit an existing item image, the image maintains its original size and does not get resized. Each version of the image, be it xs, s, m, l or xl retains the size of the original image uploaded.

As all worked well on the old server, I guess that we have a sever or php issue. Can anyone point me in the right direction?

Thanks

You can check your server's error log for any errors.
Ensure you have the GD image library installed and you have allocated enough memory for image resizing.

You should also address this issue to your hosting provider.